Although double immunofluorescence have shown that Hes1, a downstream target of Notch1 signaling, was expressed in Sox2- and Oct4-positive cells in human primary NPC tissue [50], the present study was the first one demonstrating that the expression of Hes1 was significantly increased in NPC biopsies compared to normal tissues. Here, NOTCH1 is linked to nasopharyngeal carcinoma.